Although extensive research efforts since the early 1970s have explored the causal relationship between narcotic use and property crime, the relationship between drug use patterns generally and related criminal involvement is not well understood. A low-cost feasibility study is proposed using arrestee data obtained from an on-going needs assessment survey conducted as part of the California Drug Use Forecasting (CAL-DUF) Program, funded for data collection by the National Institute of Justice and the Substance Abuse and Mental Health Service Administration, Center for Substance Abuse Treatment. The proposed research will examine the relationships between drug use by arrestees and their official criminal histories through analysis of existing data from two sources. The first source is a full year of DUF data collection, augmented by extensive additional information, is Los Angeles County for the period July 1, 1994 through June 30, 1995 (N=1289). The second source is longitudinal data ("rap sheets") routinely collected on all arrests in California by the Bureau of Criminal Statistic. (BCS) and organized both chronologically and by individual. This data base has automated information from 1972 to the present. Secondary analysis of the data resulting from merging these two sources at the individual arrestee level will: (1) Examine the association between drug use and criminal history, as represented by arrests: (2) Identify the drug-crime arrest patterns from initiation, progression, cessation, and resumption of the drug use and criminal careers, documenting the frequency, timing, and types of criminal activity; and (3) Assess the effects of demographic, situational, and psychosocial variables in moderating or mediating the identified patterns of the drug-crime relationship. The proposed research will yield both substantive and practical contributions that are likely to be of interest to many in the research, criminal justice, and drug treatment communities. It will indicate potential causal relationships between drug use and crime that merit further research, nd it will suggest ways to improve crime control interventions for drug-using offenders.